The catalog pg_language registers
languages in which you can write functions or stored procedures.
See CREATE
LANGUAGE and Chapter 35 for more
information about language handlers.

Table 42-20. pg_language Columns

Name

Type

References

Description

lanname

name

Name of the language

lanispl

bool

This is false for internal languages (such as
SQL) and true for
user-defined languages. Currently, pg_dump still uses this to determine
which languages need to be dumped, but this may be
replaced by a different mechanism sometime.

lanpltrusted

bool

True if this is a trusted language, which means that
it is believed not to grant access to anything outside
the normal SQL execution environment. Only superusers may
create functions in untrusted languages.